Improvement in steam-boilers



UNITED STATES PATENT OFFICE.

FRANCIS BROVN BLANCHARD, OF BROOKLYN, YNEW YORK.

IMPROVEMENT IN STEAM-BOILERS.

Specification forming part of VLetters Patent No. 31,561, dated April 2,1861.

To all whom t may concern.:

Be it known that I, FRANcIs BROWN BLANCHARD, of the city of Brooklyn, inthe county of Kings and State of New York, have invented certain new anduseful Improvements in Steam-Boilers; and I do hereby declare that thefollowing is a full, clear, and exact ldescription of the same,reference being had to the accompanying drawing, forming part of thisspecification.

The principal objects sought to be attained by my invention are, first,to obtain in generating steam the full advantage that is to be derivedfrom the combustion of the fuel with a blast, and, second, to abstractfrom the gaseous products of combustion before their escape to theatmosphere the greatest practicable amount of heat in the most effectivemanner; and to these ends the nature of my invention consists in theemployment, in combination with a steam-boiler of any known or suitableconstruction having its furnace `closed to the atmosphere, but suppliedwith air by a blast apparatus, and having no chimney, or having suitableappliances for closing its chimney, if any is provided, of a steamheaterand a feed-water heater, through which the gaseous products ofcombustion are driven in succession by the force of the blast, first,

through the steam-heater to convert into Y steam any water that may havebeen taken up in suspension from the boiler, and to superheat the steamto a desirable degree, and afterward through the water-heater to raisethe temperature of the feed-water before its introduction to the boilerand from thence to the atmosphere, the surfaces of the said heat- 'ersbeing so proportioned as to take up from `the escaping gaseous productsof combustion nearly all the heat that ordinarily passes off by thechimney. The accompanying drawing represents a vertical section of asteaimgenerating apparatus, illustrating the Inode of carrying out myinvention,the parts of the same being arf ranged more with a view to theexplanation of .the connection. between the several parts than to theirpractical operation. The boiler therein represented is of the horizontalmultitubular kind. p

A is the fire-box, and B the ashpit, both of which are closed, except tothe two pipes c and l) of the ainccmpression pump C, one of the saidpipes entering below and the other above the gate K. These pipes mayhave cocks to regulate the supply of air above and below the grate, asmay be necessary.

D D are tubes leading from the fire-box A to the smoke box or chamber E,on the top of which is a chimney, F, which is of ordinary size, but isprovided with a valve or valves, G, by which it can be closed atpleasure through the agency of a lever or other suitable apparatus..

H is the steam-heater, which may be variously constructedto expose thesteam admitted from the boiler by the pipe c to surfaces heated by thegaseous products of cornbustion admitted from the-chamber E by a pipe,CZ. The construction of the steam-heater represented is that of acylinder with two hollow heads, e f, connected by a series of tubes, gg, and the steam is admitted by the pipe c between the heads and amongthe tubes, and the products of combustion are admitted by the pipe dinto the head e, from whence they pass along the tubes gg into the headf, from whence they escape by the pipe h to the feed-water heater l,while the steam is conveyed'away to the steamengineor for other use bythe pipe e'.

The feed-water heater I may yalso be variously constructed to bring thewater introduced by the feed-pump through the pipe j into contact withsurfaces heated by the gaseous products of combustion; but it isrepresented as constructed like the steamheater H. The gaseous productsof combustion enter by the pipe h into the hollow head K and pass fromthence through the tubes ZZ into the hollow head m, from whence it es*capes by the pipe n to the atmosphere.- The Awater is introduced by thepipe j among the tubes Z Z and between the heads K m, and passes fromthence to the boiler by the pipe p.

The fuel may be introduced into the furnace by a feeder such as isdescribed in the schedule of my Letters Patent No. 13,209, or of othersuitable construction which permits it to be introduced'without theadmission of air or escape of the gases of combustion at the place ofits introduction. Such a feeder it is not necessary here to describe, asit forms no part of this invention..

Instead of using this 2 al ,sel

feeder, however, means may be provided for shutting off the air topermit the introduction of the fuel at an ordinary door in the fire-box.At the time of lighting the lire the chimneyvalve G is to be open topermit a free draft, either natural or artificial, and this valve is toremain open till steam enough is generated to start the engine intendedto be supplied by the generating apparatus or to commence the operationintended to be effected by such steam and to set in action the air-pumpC or other blowing apparatus when the chimneyvalve G is shut and thefurnace closed up against the admission of air by any other means thanthe pipes a b from the blowingcylinder. This pump is intended to loe ofsuch capacity and its operation to be so controlled as to supply to thefurnace only about the necessary quantity of air to effect thecombustion of the necessary quantity of fuel, so that as little heat aspossible may be taken up and carried off as so much waste by an excessof air which would pass off unconsuined. The furnace being closed andthe blowing apparatus set in operation, air is su pplied to the furnaceas fast as, and no faster than, is required, and, being supplied amongthe gases above the fire-bed as well as below the grate,very perfectcombustion is effected. The gaseous products of combustion are driven bythe force of the blast through the tubes of the boiler and through thepipe CZ to and through the tubes of the steam and water hea'ters andfinally expelled through the pipe n, all as indicated by the blackarrows in the drawing, and by the extent of surface presented by theheaters the heat of the gaseous products is nearly all used, theirtemperature being so far reduced that they are practically incapable ofcontributing any further to the generation of steam. Whenever thesteampipe which conveys the steam to the engine or other apparatusoperated by the boiler is closed, the chimney-valve and the furnaceshould be opened to permit a suicient natural draft to prevent the firegoing out and to carry o the products of combustion by the chimney,instead of through the heaters, so as to obviate all danger of burningthe steam-heater or heating the steam excessively.

By the use of the artificial supply of air or blast in combination withthe use of steam and water heaters so applied that the whole of thegaseous products of combustion are driven through them by the blastinstead of being permitted to escape by the ordinary chimney, and whichhave their surfaces so proportioned as to abstract from the saidproducts nearly all their heat, I obtain very important results ascompared with what is obtained by the use of the blast with an ordinaryopen chimney, for in that use of the blast, notwithstanding that agreater amount of available heat is obtained from and more steamgenerated by a given quantity of fuel n than when a natural draft isused, the gaseous products escape at a still higher temperature, while'Inot only obtain all the advantage to be derived from the use of theblast in that way, but save most of the immense amount of heat therebypermitted to escape from the chimney, as the gaseous products afterpassing the heaters have a temperature far below what would beadmissible with a natural draft.

yAnother important result obtained by the use of the closed furnace andchimney with the artificial supply of air in combination with the steamand water heaters, as described, is that the blowing-cylinder or votherblast apparatus driven by the engine can be made to introduce a certainmeasured quantity of air to the furnace for each revolution of theengine and a certain exact quantityof fuel will be burned and aproportional quantity of water will be converted into steam for eachrevolution, and this quantity of steam passing into the steam-heatersand being there subjected to the action of gases of quantity, quality,and temperature always the same,

' will insure a certain temperature of the superheated steam, and hencethe heating-surfaces of the boiler and the heater may be properlyproportioned t-o produce any desired constant pressure and temperatureof steam, and there is no danger of burning or overheating thesuperheating-pipes or heating the steam eX- cessively. By thuscontrolling the temperature of steam I am enabled to use the principleof expansion of gases by heat to the fullest extent that is practicableand maintain proper lubrication of the engine. The natural draft withopen chimney is not capable of producing such a constantly-uniformtemperature and constant and uniform generation and superheating of thesteam, for it is dependent on, the condition of the atmosphere and onthe mode of firing, and when an artiiicial supply of air is used with anopen chimney the effect is but little improved. By having thesteam-heater and the water-heater applied in connection with a separateoutlet from the furnace and providing another outlet to an ordinarychimney, which can be opened when the engine is stopped or thesteam-pipe closed, at which time, from the cessation of the circulationof the steam through the heater, the great danger of burning it islikely to occur, the liability of burning the heater, which has here-'tofore been the greatest obstacle to the use of superheated steam, isobviated.

I do not claim, broadly, the use of a closed furnace and chimney appliedto a steamboiler; nor-do I claim, broadly, the employment of theescaping hot products of combnstion from a steam-boiler furnace to heata vessel through which the steam is caused to pass after leaving theboiler, for the purpose of evaporating the water that may have beentaken up in suspension by it and of superheating it. Neither do I claimthe use of such escaping products of combustion to Water-heaterandsteam-heater with eachother heat the feed-Water before its introductionto and with Jche boiler, air-pump, and chimney, the boiler; but all asset forth.

WhatI claim as my invention, anddesire to FRANCIS BROVN BLANCARD. secureby Letters Patent, is- Witnesses:

The combination, in the manner substan- WM. TUSCH,

tially as herein shown and described, of the R. S. SPENCER.

